This application claims the priority of German patent document 103 33 603.6, filed Jul. 24, 2003, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a system having a device for actuating a stop/start unit for operating a combustion engine.
Automatic stop/start units are used particularly in motor vehicles in order to save power when switching off an internal-combustion engine during traffic light phases or in congested traffic. However, if switch-off phases are too short, the saving of power is overcompensated by an expenditure of power during the start of the internal-combustion engine. It is therefore particularly important to recognize a driving situation, and to adapt the operation of the automatic stop/start unit to the driving situation.
German Patent Document DE 101 61 343 A1 discloses a system which has a control unit for actuating an automatic stop/start unit for an internal-combustion engine with a transmission. The automatic stop/start unit comprises a starter for starting the internal-combustion engine and an interruption unit for interrupting a fuel supply. Several sensors are provided for detecting parameters as a function of which the stop/start unit is actuated during the operation.
The internal-combustion engine is stopped automatically when an automatic stopping condition has been met while the internal-combustion engine is running, and is started automatically when an automatic starting condition has been met. The stop condition has been met when all of the following individual conditions have been satisfied: (1) The vehicle speed is lower than a desired value, which differs from zero; (2) an idling switch is switched on; and (3) a drive position of the transmission corresponds to a neutral position.
The automatic start condition has been met when one of the following individual conditions has been met: (1) The clutch is changed into a disengaged condition, starting from a completely engaged or semi-engaged condition; (2) the drive position of the transmission is not the neutral position; (3) an idling switch is switched off; or (4) the condition of a booster vacuum is present.
One object of the invention is to provide an improved automatic stop/start unit, with improved adaptation to various driving situations, particularly maneuvering situations and traffic jam situations.
This and other objects and advantages are achieved by the invention which includes a regulating and/or control unit for actuating a stop/start unit, particularly for an internal-combustion engine of a motor vehicle. At least one sensor is provided for detecting at least one parameter, as a function of which the unit actuates the stop/start unit during operation.
In one embodiment of the invention, the sensor detects a parameter which depends on a steering wheel position and/or a steering wheel movement of the motor vehicle. Based on this information, it is possible to detect a driving situation, such as a maneuvering situation, and to distinguish it from a traffic jam situation. If a maneuvering situation has been detected based on steering behavior, the related information can (for example, by way of a CAN bus of the motor vehicle) also be utilized by other control and regulating units of the motor vehicle. The person skilled in the art will recognize that the unit can be a component which is separate from the stop/start unit, or can at least partially be integrated into the latter, particularly in a control and/or regulating unit of the stop/start unit.
In a further embodiment of the invention, the regulating and/or control unit deactivates at least one function of the stop/start unit when the parameters, particularly a steering angle and/or a steering speed, in each case, exceed at least one threshold value. As a result, it is possible in a simple manner, to distinguish between a traffic jam, which is typically characterized by small steering angles and steering speeds and a maneuvering situation, with large steering angles and steering speeds. Expediently, two threshold values are provided respectively, which include an interval of steering wheel positions and/or steering speeds, and the unit deactivates an automatic stop function of the stop/start unit as soon as the amount of the steering angle and/or of the steering speed exceeds a threshold value.
In still another embodiment of the invention, the regulating and/or control unit has at least one sensor which detects a parameter for driving speed, as a function which the unit actuates the stop/start unit during the operation. As a result, it is possible to avoid mistaking a fast drive of the motor vehicle on a winding road for a maneuvering situation, which can be detected with still greater certainty.
According to another embodiment of the invention, a sensor is provided for the detection of a drive position parameter, as a function of which the unit actuates the stop/start unit during the operation. The stop/start unit can advantageously be deactivated as soon as the transmission is shifted into a reversing position which occurs almost exclusively in maneuvering situations.
The system may also be equipped with a time measuring device, and the regulating and/or control unit activates the stop/start unit as a function of at least one detected time during the operation. A deactivated stop function of the stop/start unit can advantageously be activated after a preadjusted time period, which can be determined from experimental values for the time required for a maneuvering operation.
In one embodiment of the invention, at least one threshold value is automatically and/or manually adjustable, so that the device can be adapted to driving situations determined from additional parameters or to individual driving habits of a vehicle driver.
According to a further feature of the invention, the regulating and/or control unit is constructed to actuate a hybrid machine. In a detected maneuvering situation, an operating mode of the engine designed for driving situations can advantageously be replaced by a particularly economical operating mode of the engine designed for maneuvering situations.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.